There are situations wherein several persons are seriously wounded or injured simultaneously. This may happen in war zones or owing to a road accident, for instance. In such cases, it is important to be able to establish easily and reliably who among the injured or wounded is or are most in need of help, in other words closest to losing their lives, so as to enable such a person or persons to be helped first.
When a person's vital functions are threatened with coming to an end e.g. because of a bleeding wound, the heart tries to pump blood to the circulation at a high pace. In such a case, the heart beat frequency, i.e. heart rate or pulse, increases rapidly. A known manner to find these wounded or injured persons most in need of help is thus to try their pulse by using a finger on the jugular area, for instance. This, however, takes a lot of time, since in practice there may be several people to be monitored simultaneously. In addition, the aforementioned manner is unreliable since no pulse is necessarily found by the finger technique at once, a person's own pulse may influence the indication of another person's pulse, and the person taking the pulse should be capable of distinguishing differences in the heart rates of several different people. Furthermore, the aforementioned manner subjects a patient's jugular area to air, which may be cold.
It is also known to detect a pulse by using a stethoscope, but background noise is very often so overwhelming that in practice pulse detection by hearing is not reliable.
It is also known to measure a heart rate by means of heart rate monitors for athletes. These, however, are expensive, and it is time-consuming to place such a device on a wounded person.
A disposable heart beat detection device is known from WO 03024325. The heart beat is indicated by means of light or sound signals. This solution has at least the problem that a wounded person is to be undressed in the area of the heart beat detection device (e.g. in the thorax area) so as to enable the heart beat to be detected visually by means of light signals emitted by the heart beat detection device. Further, the wounded person has to lie down with his or her back towards the ground in order for the heart beat detection area to be facing upwards and thus in order for the light signal to be visible.
It is thus important to find a faster, more reliable, and more user-friendly method of indicating a heart rate.